arch/um/drivers/line.c

   1 /*
   2  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/irqreturn.h"
   7 #include "linux/kd.h"
   8 #include "linux/sched.h"
   9 #include "linux/slab.h"
  10 #include "chan_kern.h"
  11 #include "irq_kern.h"
  12 #include "irq_user.h"
  13 #include "kern_util.h"
  14 #include "os.h"
  15
  16 #define LINE_BUFSIZE 4096
  17
  18 static irqreturn_t line_interrupt(int irq, void *data)
  19 {
  20         struct chan *chan = data;
  21         struct line *line = chan->line;
  22
  23         if (line)
  24                 chan_interrupt(&line->chan_list, &line->task, line->tty, irq);
  25         return IRQ_HANDLED;
  26 }
  27
  28 static void line_timer_cb(struct work_struct *work)
  29 {
  30         struct line *line = container_of(work, struct line, task.work);
  31
  32         if (!line->throttled)
  33                 chan_interrupt(&line->chan_list, &line->task, line->tty,
  34                                line->driver->read_irq);
  35 }
  36
  37 /*
  38  * Returns the free space inside the ring buffer of this line.
  39  *
  40  * Should be called while holding line->lock (this does not modify data).
  41  */
  42 static int write_room(struct line *line)
  43 {
  44         int n;
  45
  46         if (line->buffer == NULL)
  47                 return LINE_BUFSIZE - 1;
  48
  49         /* This is for the case where the buffer is wrapped! */
  50         n = line->head - line->tail;
  51
  52         if (n <= 0)
  53                 n += LINE_BUFSIZE; /* The other case */
  54         return n - 1;
  55 }
  56
  57 int line_write_room(struct tty_struct *tty)
  58 {
  59         struct line *line = tty->driver_data;
  60         unsigned long flags;
  61         int room;
  62
  63         spin_lock_irqsave(&line->lock, flags);
  64         room = write_room(line);
  65         spin_unlock_irqrestore(&line->lock, flags);
  66
  67         return room;
  68 }
  69
  70 int line_chars_in_buffer(struct tty_struct *tty)
  71 {
  72         struct line *line = tty->driver_data;
  73         unsigned long flags;
  74         int ret;
  75
  76         spin_lock_irqsave(&line->lock, flags);
  77         /* write_room subtracts 1 for the needed NULL, so we readd it.*/
  78         ret = LINE_BUFSIZE - (write_room(line) + 1);
  79         spin_unlock_irqrestore(&line->lock, flags);
  80
  81         return ret;
  82 }
  83
  84 /*
  85  * This copies the content of buf into the circular buffer associated with
  86  * this line.
  87  * The return value is the number of characters actually copied, i.e. the ones
  88  * for which there was space: this function is not supposed to ever flush out
  89  * the circular buffer.
  90  *
  91  * Must be called while holding line->lock!
  92  */
  93 static int buffer_data(struct line *line, const char *buf, int len)
  94 {
  95         int end, room;
  96
  97         if (line->buffer == NULL) {
  98                 line->buffer = kmalloc(LINE_BUFSIZE, GFP_ATOMIC);
  99                 if (line->buffer == NULL) {
 100                         printk(KERN_ERR "buffer_data - atomic allocation "
 101                                "failed\n");
 102                         return 0;
 103                 }
 104                 line->head = line->buffer;
 105                 line->tail = line->buffer;
 106         }
 107
 108         room = write_room(line);
 109         len = (len > room) ? room : len;
 110
 111         end = line->buffer + LINE_BUFSIZE - line->tail;
 112
 113         if (len < end) {
 114                 memcpy(line->tail, buf, len);
 115                 line->tail += len;
 116         }
 117         else {
 118                 /* The circular buffer is wrapping */
 119                 memcpy(line->tail, buf, end);
 120                 buf += end;
 121                 memcpy(line->buffer, buf, len - end);
 122                 line->tail = line->buffer + len - end;
 123         }
 124
 125         return len;
 126 }
 127
 128 /*
 129  * Flushes the ring buffer to the output channels. That is, write_chan is
 130  * called, passing it line->head as buffer, and an appropriate count.
 131  *
 132  * On exit, returns 1 when the buffer is empty,
 133  * 0 when the buffer is not empty on exit,
 134  * and -errno when an error occurred.
 135  *
 136  * Must be called while holding line->lock!*/
 137 static int flush_buffer(struct line *line)
 138 {
 139         int n, count;
 140
 141         if ((line->buffer == NULL) || (line->head == line->tail))
 142                 return 1;
 143
 144         if (line->tail < line->head) {
 145                 /* line->buffer + LINE_BUFSIZE is the end of the buffer! */
 146                 count = line->buffer + LINE_BUFSIZE - line->head;
 147
 148                 n = write_chan(&line->chan_list, line->head, count,
 149                                line->driver->write_irq);
 150                 if (n < 0)
 151                         return n;
 152                 if (n == count) {
 153                         /*
 154                          * We have flushed from ->head to buffer end, now we
 155                          * must flush only from the beginning to ->tail.
 156                          */
 157                         line->head = line->buffer;
 158                 } else {
 159                         line->head += n;
 160                         return 0;
 161                 }
 162         }
 163
 164         count = line->tail - line->head;
 165         n = write_chan(&line->chan_list, line->head, count,
 166                        line->driver->write_irq);
 167
 168         if (n < 0)
 169                 return n;
 170
 171         line->head += n;
 172         return line->head == line->tail;
 173 }
 174
 175 void line_flush_buffer(struct tty_struct *tty)
 176 {
 177         struct line *line = tty->driver_data;
 178         unsigned long flags;
 179
 180         spin_lock_irqsave(&line->lock, flags);
 181         flush_buffer(line);
 182         spin_unlock_irqrestore(&line->lock, flags);
 183 }
 184
 185 /*
 186  * We map both ->flush_chars and ->put_char (which go in pair) onto
 187  * ->flush_buffer and ->write. Hope it's not that bad.
 188  */
 189 void line_flush_chars(struct tty_struct *tty)
 190 {
 191         line_flush_buffer(tty);
 192 }
 193
 194 int line_put_char(struct tty_struct *tty, unsigned char ch)
 195 {
 196         return line_write(tty, &ch, sizeof(ch));
 197 }
 198
 199 int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
 200 {
 201         struct line *line = tty->driver_data;
 202         unsigned long flags;
 203         int n, ret = 0;
 204
 205         spin_lock_irqsave(&line->lock, flags);
 206         if (line->head != line->tail)
 207                 ret = buffer_data(line, buf, len);
 208         else {
 209                 n = write_chan(&line->chan_list, buf, len,
 210                                line->driver->write_irq);
 211                 if (n < 0) {
 212                         ret = n;
 213                         goto out_up;
 214                 }
 215
 216                 len -= n;
 217                 ret += n;
 218                 if (len > 0)
 219                         ret += buffer_data(line, buf + n, len);
 220         }
 221 out_up:
 222         spin_unlock_irqrestore(&line->lock, flags);
 223         return ret;
 224 }
 225
 226 void line_set_termios(struct tty_struct *tty, struct ktermios * old)
 227 {
 228         /* nothing */
 229 }
 230
 231 static const struct {
 232         int  cmd;
 233         char *level;
 234         char *name;
 235 } tty_ioctls[] = {
 236         /* don't print these, they flood the log ... */
 237         { TCGETS,      NULL,       "TCGETS"      },
 238         { TCSETS,      NULL,       "TCSETS"      },
 239         { TCSETSW,     NULL,       "TCSETSW"     },
 240         { TCFLSH,      NULL,       "TCFLSH"      },
 241         { TCSBRK,      NULL,       "TCSBRK"      },
 242
 243         /* general tty stuff */
 244         { TCSETSF,     KERN_DEBUG, "TCSETSF"     },
 245         { TCGETA,      KERN_DEBUG, "TCGETA"      },
 246         { TIOCMGET,    KERN_DEBUG, "TIOCMGET"    },
 247         { TCSBRKP,     KERN_DEBUG, "TCSBRKP"     },
 248         { TIOCMSET,    KERN_DEBUG, "TIOCMSET"    },
 249
 250         /* linux-specific ones */
 251         { TIOCLINUX,   KERN_INFO,  "TIOCLINUX"   },
 252         { KDGKBMODE,   KERN_INFO,  "KDGKBMODE"   },
 253         { KDGKBTYPE,   KERN_INFO,  "KDGKBTYPE"   },
 254         { KDSIGACCEPT, KERN_INFO,  "KDSIGACCEPT" },
 255 };
 256
 257 int line_ioctl(struct tty_struct *tty, unsigned int cmd,
 258                                 unsigned long arg)
 259 {
 260         int ret;
 261         int i;
 262
 263         ret = 0;
 264         switch(cmd) {
 265 #ifdef TIOCGETP
 266         case TIOCGETP:
 267         case TIOCSETP:
 268         case TIOCSETN:
 269 #endif
 270 #ifdef TIOCGETC
 271         case TIOCGETC:
 272         case TIOCSETC:
 273 #endif
 274 #ifdef TIOCGLTC
 275         case TIOCGLTC:
 276         case TIOCSLTC:
 277 #endif
 278         /* Note: these are out of date as we now have TCGETS2 etc but this
 279            whole lot should probably go away */
 280         case TCGETS:
 281         case TCSETSF:
 282         case TCSETSW:
 283         case TCSETS:
 284         case TCGETA:
 285         case TCSETAF:
 286         case TCSETAW:
 287         case TCSETA:
 288         case TCXONC:
 289         case TCFLSH:
 290         case TIOCOUTQ:
 291         case TIOCINQ:
 292         case TIOCGLCKTRMIOS:
 293         case TIOCSLCKTRMIOS:
 294         case TIOCPKT:
 295         case TIOCGSOFTCAR:
 296         case TIOCSSOFTCAR:
 297                 return -ENOIOCTLCMD;
 298 #if 0
 299         case TCwhatever:
 300                 /* do something */
 301                 break;
 302 #endif
 303         default:
 304                 for (i = 0; i < ARRAY_SIZE(tty_ioctls); i++)
 305                         if (cmd == tty_ioctls[i].cmd)
 306                                 break;
 307                 if (i == ARRAY_SIZE(tty_ioctls)) {
 308                         printk(KERN_ERR "%s: %s: unknown ioctl: 0x%x\n",
 309                                __func__, tty->name, cmd);
 310                 }
 311                 ret = -ENOIOCTLCMD;
 312                 break;
 313         }
 314         return ret;
 315 }
 316
 317 void line_throttle(struct tty_struct *tty)
 318 {
 319         struct line *line = tty->driver_data;
 320
 321         deactivate_chan(&line->chan_list, line->driver->read_irq);
 322         line->throttled = 1;
 323 }
 324
 325 void line_unthrottle(struct tty_struct *tty)
 326 {
 327         struct line *line = tty->driver_data;
 328
 329         line->throttled = 0;
 330         chan_interrupt(&line->chan_list, &line->task, tty,
 331                        line->driver->read_irq);
 332
 333         /*
 334          * Maybe there is enough stuff pending that calling the interrupt
 335          * throttles us again.  In this case, line->throttled will be 1
 336          * again and we shouldn't turn the interrupt back on.
 337          */
 338         if (!line->throttled)
 339                 reactivate_chan(&line->chan_list, line->driver->read_irq);
 340 }
 341
 342 static irqreturn_t line_write_interrupt(int irq, void *data)
 343 {
 344         struct chan *chan = data;
 345         struct line *line = chan->line;
 346         struct tty_struct *tty = line->tty;
 347         int err;
 348
 349         /*
 350          * Interrupts are disabled here because we registered the interrupt with
 351          * IRQF_DISABLED (see line_setup_irq).
 352          */
 353
 354         spin_lock(&line->lock);
 355         err = flush_buffer(line);
 356         if (err == 0) {
 357                 return IRQ_NONE;
 358         } else if (err < 0) {
 359                 line->head = line->buffer;
 360                 line->tail = line->buffer;
 361         }
 362         spin_unlock(&line->lock);
 363
 364         if (tty == NULL)
 365                 return IRQ_NONE;
 366
 367         tty_wakeup(tty);
 368         return IRQ_HANDLED;
 369 }
 370
 371 int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
 372 {
 373         const struct line_driver *driver = line->driver;
 374         int err = 0, flags = IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM;
 375
 376         if (input)
 377                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
 378                                        line_interrupt, flags,
 379                                        driver->read_irq_name, data);
 380         if (err)
 381                 return err;
 382         if (output)
 383                 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
 384                                         line_write_interrupt, flags,
 385                                         driver->write_irq_name, data);
 386         line->have_irq = 1;
 387         return err;
 388 }
 389
 390 /*
 391  * Normally, a driver like this can rely mostly on the tty layer
 392  * locking, particularly when it comes to the driver structure.
 393  * However, in this case, mconsole requests can come in "from the
 394  * side", and race with opens and closes.
 395  *
 396  * mconsole config requests will want to be sure the device isn't in
 397  * use, and get_config, open, and close will want a stable
 398  * configuration.  The checking and modification of the configuration
 399  * is done under a spinlock.  Checking whether the device is in use is
 400  * line->tty->count > 1, also under the spinlock.
 401  *
 402  * line->count serves to decide whether the device should be enabled or
 403  * disabled on the host.  If it's equal to 0, then we are doing the
 404  * first open or last close.  Otherwise, open and close just return.
 405  */
 406
 407 int line_open(struct line *lines, struct tty_struct *tty)
 408 {
 409         struct line *line = &lines[tty->index];
 410         int err = -ENODEV;
 411
 412         spin_lock(&line->count_lock);
 413         if (!line->valid)
 414                 goto out_unlock;
 415
 416         err = 0;
 417         if (line->count++)
 418                 goto out_unlock;
 419
 420         BUG_ON(tty->driver_data);
 421         tty->driver_data = line;
 422         line->tty = tty;
 423
 424         spin_unlock(&line->count_lock);
 425         err = enable_chan(line);
 426         if (err) /* line_close() will be called by our caller */
 427                 return err;
 428
 429         INIT_DELAYED_WORK(&line->task, line_timer_cb);
 430
 431         if (!line->sigio) {
 432                 chan_enable_winch(&line->chan_list, tty);
 433                 line->sigio = 1;
 434         }
 435
 436         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 437                          &tty->winsize.ws_col);
 438
 439         return 0;
 440
 441 out_unlock:
 442         spin_unlock(&line->count_lock);
 443         return err;
 444 }
 445
 446 static void unregister_winch(struct tty_struct *tty);
 447
 448 void line_close(struct tty_struct *tty, struct file * filp)
 449 {
 450         struct line *line = tty->driver_data;
 451
 452         /*
 453          * If line_open fails (and tty->driver_data is never set),
 454          * tty_open will call line_close.  So just return in this case.
 455          */
 456         if (line == NULL)
 457                 return;
 458
 459         /* We ignore the error anyway! */
 460         flush_buffer(line);
 461
 462         spin_lock(&line->count_lock);
 463         BUG_ON(!line->valid);
 464
 465         if (--line->count)
 466                 goto out_unlock;
 467
 468         line->tty = NULL;
 469         tty->driver_data = NULL;
 470
 471         spin_unlock(&line->count_lock);
 472
 473         if (line->sigio) {
 474                 unregister_winch(tty);
 475                 line->sigio = 0;
 476         }
 477
 478         return;
 479
 480 out_unlock:
 481         spin_unlock(&line->count_lock);
 482 }
 483
 484 void close_lines(struct line *lines, int nlines)
 485 {
 486         int i;
 487
 488         for(i = 0; i < nlines; i++)
 489                 close_chan(&lines[i].chan_list, 0);
 490 }
 491
 492 static int setup_one_line(struct line *lines, int n, char *init, int init_prio,
 493                           char **error_out)
 494 {
 495         struct line *line = &lines[n];
 496         int err = -EINVAL;
 497
 498         spin_lock(&line->count_lock);
 499
 500         if (line->count) {
 501                 *error_out = "Device is already open";
 502                 goto out;
 503         }
 504
 505         if (line->init_pri <= init_prio) {
 506                 line->init_pri = init_prio;
 507                 if (!strcmp(init, "none"))
 508                         line->valid = 0;
 509                 else {
 510                         line->init_str = init;
 511                         line->valid = 1;
 512                 }
 513         }
 514         err = 0;
 515 out:
 516         spin_unlock(&line->count_lock);
 517         return err;
 518 }
 519
 520 /*
 521  * Common setup code for both startup command line and mconsole initialization.
 522  * @lines contains the array (of size @num) to modify;
 523  * @init is the setup string;
 524  * @error_out is an error string in the case of failure;
 525  */
 526
 527 int line_setup(struct line *lines, unsigned int num, char *init,
 528                char **error_out)
 529 {
 530         int i, n, err;
 531         char *end;
 532
 533         if (*init == '=') {
 534                 /*
 535                  * We said con=/ssl= instead of con#=, so we are configuring all
 536                  * consoles at once.
 537                  */
 538                 n = -1;
 539         }
 540         else {
 541                 n = simple_strtoul(init, &end, 0);
 542                 if (*end != '=') {
 543                         *error_out = "Couldn't parse device number";
 544                         return -EINVAL;
 545                 }
 546                 init = end;
 547         }
 548         init++;
 549
 550         if (n >= (signed int) num) {
 551                 *error_out = "Device number out of range";
 552                 return -EINVAL;
 553         }
 554         else if (n >= 0) {
 555                 err = setup_one_line(lines, n, init, INIT_ONE, error_out);
 556                 if (err)
 557                         return err;
 558         }
 559         else {
 560                 for(i = 0; i < num; i++) {
 561                         err = setup_one_line(lines, i, init, INIT_ALL,
 562                                              error_out);
 563                         if (err)
 564                                 return err;
 565                 }
 566         }
 567         return n == -1 ? num : n;
 568 }
 569
 570 int line_config(struct line *lines, unsigned int num, char *str,
 571                 const struct chan_opts *opts, char **error_out)
 572 {
 573         struct line *line;
 574         char *new;
 575         int n;
 576
 577         if (*str == '=') {
 578                 *error_out = "Can't configure all devices from mconsole";
 579                 return -EINVAL;
 580         }
 581
 582         new = kstrdup(str, GFP_KERNEL);
 583         if (new == NULL) {
 584                 *error_out = "Failed to allocate memory";
 585                 return -ENOMEM;
 586         }
 587         n = line_setup(lines, num, new, error_out);
 588         if (n < 0)
 589                 return n;
 590
 591         line = &lines[n];
 592         return parse_chan_pair(line->init_str, line, n, opts, error_out);
 593 }
 594
 595 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
 596                     int size, char **error_out)
 597 {
 598         struct line *line;
 599         char *end;
 600         int dev, n = 0;
 601
 602         dev = simple_strtoul(name, &end, 0);
 603         if ((*end != '\0') || (end == name)) {
 604                 *error_out = "line_get_config failed to parse device number";
 605                 return 0;
 606         }
 607
 608         if ((dev < 0) || (dev >= num)) {
 609                 *error_out = "device number out of range";
 610                 return 0;
 611         }
 612
 613         line = &lines[dev];
 614
 615         spin_lock(&line->count_lock);
 616         if (!line->valid)
 617                 CONFIG_CHUNK(str, size, n, "none", 1);
 618         else if (line->tty == NULL)
 619                 CONFIG_CHUNK(str, size, n, line->init_str, 1);
 620         else n = chan_config_string(&line->chan_list, str, size, error_out);
 621         spin_unlock(&line->count_lock);
 622
 623         return n;
 624 }
 625
 626 int line_id(char **str, int *start_out, int *end_out)
 627 {
 628         char *end;
 629         int n;
 630
 631         n = simple_strtoul(*str, &end, 0);
 632         if ((*end != '\0') || (end == *str))
 633                 return -1;
 634
 635         *str = end;
 636         *start_out = n;
 637         *end_out = n;
 638         return n;
 639 }
 640
 641 int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
 642 {
 643         int err;
 644         char config[sizeof("conxxxx=none\0")];
 645
 646         sprintf(config, "%d=none", n);
 647         err = line_setup(lines, num, config, error_out);
 648         if (err >= 0)
 649                 err = 0;
 650         return err;
 651 }
 652
 653 struct tty_driver *register_lines(struct line_driver *line_driver,
 654                                   const struct tty_operations *ops,
 655                                   struct line *lines, int nlines)
 656 {
 657         int i;
 658         struct tty_driver *driver = alloc_tty_driver(nlines);
 659
 660         if (!driver)
 661                 return NULL;
 662
 663         driver->driver_name = line_driver->name;
 664         driver->name = line_driver->device_name;
 665         driver->major = line_driver->major;
 666         driver->minor_start = line_driver->minor_start;
 667         driver->type = line_driver->type;
 668         driver->subtype = line_driver->subtype;
 669         driver->flags = TTY_DRIVER_REAL_RAW;
 670         driver->init_termios = tty_std_termios;
 671         tty_set_operations(driver, ops);
 672
 673         if (tty_register_driver(driver)) {
 674                 printk(KERN_ERR "register_lines : can't register %s driver\n",
 675                        line_driver->name);
 676                 put_tty_driver(driver);
 677                 return NULL;
 678         }
 679
 680         for(i = 0; i < nlines; i++) {
 681                 if (!lines[i].valid)
 682                         tty_unregister_device(driver, i);
 683         }
 684
 685         mconsole_register_dev(&line_driver->mc);
 686         return driver;
 687 }
 688
 689 static DEFINE_SPINLOCK(winch_handler_lock);
 690 static LIST_HEAD(winch_handlers);
 691
 692 void lines_init(struct line *lines, int nlines, struct chan_opts *opts)
 693 {
 694         struct line *line;
 695         char *error;
 696         int i;
 697
 698         for(i = 0; i < nlines; i++) {
 699                 line = &lines[i];
 700                 INIT_LIST_HEAD(&line->chan_list);
 701
 702                 if (line->init_str == NULL)
 703                         continue;
 704
 705                 line->init_str = kstrdup(line->init_str, GFP_KERNEL);
 706                 if (line->init_str == NULL)
 707                         printk(KERN_ERR "lines_init - kstrdup returned NULL\n");
 708
 709                 if (parse_chan_pair(line->init_str, line, i, opts, &error)) {
 710                         printk(KERN_ERR "parse_chan_pair failed for "
 711                                "device %d : %s\n", i, error);
 712                         line->valid = 0;
 713                 }
 714         }
 715 }
 716
 717 struct winch {
 718         struct list_head list;
 719         int fd;
 720         int tty_fd;
 721         int pid;
 722         struct tty_struct *tty;
 723         unsigned long stack;
 724         struct work_struct work;
 725 };
 726
 727 static void __free_winch(struct work_struct *work)
 728 {
 729         struct winch *winch = container_of(work, struct winch, work);
 730         free_irq(WINCH_IRQ, winch);
 731
 732         if (winch->pid != -1)
 733                 os_kill_process(winch->pid, 1);
 734         if (winch->stack != 0)
 735                 free_stack(winch->stack, 0);
 736         kfree(winch);
 737 }
 738
 739 static void free_winch(struct winch *winch)
 740 {
 741         int fd = winch->fd;
 742         winch->fd = -1;
 743         if (fd != -1)
 744                 os_close_file(fd);
 745         list_del(&winch->list);
 746         __free_winch(&winch->work);
 747 }
 748
 749 static irqreturn_t winch_interrupt(int irq, void *data)
 750 {
 751         struct winch *winch = data;
 752         struct tty_struct *tty;
 753         struct line *line;
 754         int fd = winch->fd;
 755         int err;
 756         char c;
 757
 758         if (fd != -1) {
 759                 err = generic_read(fd, &c, NULL);
 760                 if (err < 0) {
 761                         if (err != -EAGAIN) {
 762                                 winch->fd = -1;
 763                                 list_del(&winch->list);
 764                                 os_close_file(fd);
 765                                 printk(KERN_ERR "winch_interrupt : "
 766                                        "read failed, errno = %d\n", -err);
 767                                 printk(KERN_ERR "fd %d is losing SIGWINCH "
 768                                        "support\n", winch->tty_fd);
 769                                 INIT_WORK(&winch->work, __free_winch);
 770                                 schedule_work(&winch->work);
 771                                 return IRQ_HANDLED;
 772                         }
 773                         goto out;
 774                 }
 775         }
 776         tty = winch->tty;
 777         if (tty != NULL) {
 778                 line = tty->driver_data;
 779                 if (line != NULL) {
 780                         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 781                                          &tty->winsize.ws_col);
 782                         kill_pgrp(tty->pgrp, SIGWINCH, 1);
 783                 }
 784         }
 785  out:
 786         if (winch->fd != -1)
 787                 reactivate_fd(winch->fd, WINCH_IRQ);
 788         return IRQ_HANDLED;
 789 }
 790
 791 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty,
 792                         unsigned long stack)
 793 {
 794         struct winch *winch;
 795
 796         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 797         if (winch == NULL) {
 798                 printk(KERN_ERR "register_winch_irq - kmalloc failed\n");
 799                 goto cleanup;
 800         }
 801
 802         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 803                                    .fd          = fd,
 804                                    .tty_fd      = tty_fd,
 805                                    .pid         = pid,
 806                                    .tty         = tty,
 807                                    .stack       = stack });
 808
 809         if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
 810                            IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
 811                            "winch", winch) < 0) {
 812                 printk(KERN_ERR "register_winch_irq - failed to register "
 813                        "IRQ\n");
 814                 goto out_free;
 815         }
 816
 817         spin_lock(&winch_handler_lock);
 818         list_add(&winch->list, &winch_handlers);
 819         spin_unlock(&winch_handler_lock);
 820
 821         return;
 822
 823  out_free:
 824         kfree(winch);
 825  cleanup:
 826         os_kill_process(pid, 1);
 827         os_close_file(fd);
 828         if (stack != 0)
 829                 free_stack(stack, 0);
 830 }
 831
 832 static void unregister_winch(struct tty_struct *tty)
 833 {
 834         struct list_head *ele, *next;
 835         struct winch *winch;
 836
 837         spin_lock(&winch_handler_lock);
 838
 839         list_for_each_safe(ele, next, &winch_handlers) {
 840                 winch = list_entry(ele, struct winch, list);
 841                 if (winch->tty == tty) {
 842                         free_winch(winch);
 843                         break;
 844                 }
 845         }
 846         spin_unlock(&winch_handler_lock);
 847 }
 848
 849 static void winch_cleanup(void)
 850 {
 851         struct list_head *ele, *next;
 852         struct winch *winch;
 853
 854         spin_lock(&winch_handler_lock);
 855
 856         list_for_each_safe(ele, next, &winch_handlers) {
 857                 winch = list_entry(ele, struct winch, list);
 858                 free_winch(winch);
 859         }
 860
 861         spin_unlock(&winch_handler_lock);
 862 }
 863 __uml_exitcall(winch_cleanup);
 864
 865 char *add_xterm_umid(char *base)
 866 {
 867         char *umid, *title;
 868         int len;
 869
 870         umid = get_umid();
 871         if (*umid == '\0')
 872                 return base;
 873
 874         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
 875         title = kmalloc(len, GFP_KERNEL);
 876         if (title == NULL) {
 877                 printk(KERN_ERR "Failed to allocate buffer for xterm title\n");
 878                 return base;
 879         }
 880
 881         snprintf(title, len, "%s (%s)", base, umid);
 882         return title;
 883 }